System and means for determination of distance and direction



Fixed Jan. s. 195o H. F. R051' EI'AL SYSI'BI AND IIEANS FOR DETERMINATION 0F DISTANCE AND DIRECTION 2 Sheets-Sheet 1 yin/FIR Av1-rfi Allg.` 4, 1953 H. F. ROST ETH. SYSTBI AND llEANS FOR DETERMINATION A 0F DISTANCE AND DIRECTION Filed Jan. s. 195o 2 shuts-sheet 2 SVTMTH GEHERATDR F/ER.

Arr/vi Patented Aug. 4, 1953 TENT OFFHCE SYSTEM AND MEANS FOR DETERMINATION F' DISTANCE AND DIRECTION Helge Fabian Rost, Djursholm, and Per Harry Elias Claessen, Jakobsberg, Sweden Application January 6,1950, Serial N o. 137,074 In Sweden February 26, 1948 (Cl. E43- 11) 6 Claims.

The present application is a continuation-inpart of our co-pending application Ser. No. 360,362, filed October 9, 1940, now Patent No. 2,536,770.

The said patent pertains to a radio object detecting system ycomprising a source of frequency modulated radio frequency energy, means for directing radioenergy in the form of a beam, means for causing said beam to scan a region proximate to said system in a cyclic manner, means for receiving the beam energy reflected by an object upon which it impinges, and for directly deriving energy from said radiating means and combining it with said reflected energy, means for frequency analysing the said combined energies, and means including a cathode ray tube connected to the scanning means and to the frequency analysing means, which are jointly controlled for producing a visual signal, which indicates simultaneously the direction and the distance of the reflecting object.

The present application refers to a system for the determination of directions and distances to objects in space, comprising in combination, means for transmitting and receiving pulse modulated radio Waves, highly directional antenna means for the transmission of said waves in a certain direction and for the reception of reflected radio waves from about the same direction as the transmitted waves, a support, means for mounting said antenna means on said support, means for rotating said antenna means at a predetermined rate about said axis, pulse generating means coupled to the transmitting and receiving means and comprising a saw-tooth generatozl and a pulse generator, and means whereby said generators are adapted to be synchronized with each other, means of indication comprising a ray indicating screen and a ray emitting source for the emission of rays projectible as visible light spots on said screen, deviation means adapted to deviate such a ray radially, and control means coupled to the receiving means for the control of the intensity of the ray, and synchronizing means coupled to the movable parts of the antenna means and to said saw-tooth generator and to the said deviation means for rotating the ray synchronously with the directional antenna means and for deviating the ray in the same instant direction as. that 0f the an' tenna means, whereby a pulse is transmittable simultaneously as the ray leaves its normal position in the direction of a reflecting object, and a light spot is produced on the screen at a distance from its normal position proportional to the distance to said reflecting object upon the receipt of a reflected Wave.

According to this invention a particularly effective arrangement is obtained, whereby the transmitting means is modulated with a pulse generator and the indicating ray is modulated with a saw-tooth generator, which in known manner are synchronized with each other. In this manner the transmitter can be modulated with very short and heavy pulses, which, however, are not suitable for the modulation of the ray-deviating means in a cathode ray tube.

Our invention will be better understood from the following description, when read in connection with the accompanying drawings, in which:

Fig. 1 shows a modication of the diagram shown in Fig. 2 of said Patent Number 2,536,770, in which the wave analyser 112 and variable condenser 113 have been replaced by an amplifier 112, and alternator 24 driven by motor 19 has been replacedby a saw-tooth generator l2@ and a pulse generator |25, which are synchronized and coupled to each other.

Fig. 2 is similar to Fig. 1 with the exception that the same radiant elements are used both for transmission and reception, shifting means |25 having been provided for shifting between transmission and reception.

In Fig. 1 a radiotransmitter I provided with a sharply directed antenna means 3, preferably of ultra short wave type, and a modulator 2 are attaohed to a rotatable axis IS. A detector l provided with'a sharply directed antenna means 5 is attached to the same rotatable axis l for receiving radio Waves transmitted by the transmitter and reflected by an object in space.

Coliectorrings 'M and l5 are arranged on the axis I8 for conducting current to circular resistance Wires or potentiometers 'l5 and ll arranged on the axis I6 and provided with brushes 8f3- 8l and 18-19 respectively. Conductors from the collector rings 14 and i5 are connected to the resistance :wires 15 and il at diametri-v cally opposite places, whereby a diameter through points 84-35 on wire 16 is located at right angles to a diameter through points 82-83 on wire 11.

The axis I6 is driven by a motor I9 and worm gear I1-I8. A pin II4 is :attached to the cogwheel I8. An arm I I is provided with an opening or slot for moving the pin I I4 back and forth.,

if cogwheel I8 is eccentrically locatedrvvith respect to axis I6.

A cathode ray oscillograph is provided with two deflecting plates |04 coupled to brushes 18e-1S of resistance wire 11.

Two other deflectingrplates 'L83 at right angles to the rst mentioned deiiecting plates `Iilll are connected to brushes 80-8I of resistance wire 1B. The resistance wires 16 and 11 are inter.'-

jconnected in a circuit forwdeectionfof Ttliecathode ray in such a manner, that 'the ,findiatlrlg ray on the fluorescent screen |82 will have exactly the same direction as the #antenna .means of the transmitter I and of the receiver igor as the Icommon antenna means ,shown in ,.2 `@for both transmitting and receiving.

A cathode ray trap diaphragm IUE 1s provided in the path of the cathode ray and electrodes iI- the 'cathode Vray tube, and an extra Vamplifier 49 can be interconnected gfor -fu-rther amplification V of the reflectedjpulses. YI'I desired, 'the ampliiier 49 can also ice-adapted to act as a rectifier.

I24--I2g5 is a pulse emitting device comprising apulse generator +25 `connectedto the modulator 2 of the Atransmitter `I randa rsaw-tooth:generator i 24 coupled to the 'ray -deviat-ing means v1I E13- |104 'over circular resistance-Wires vfl 6-11. Y

The pulse generator and thesaw-tooth generl ator are connected witheach other and synchroni'zed'for emittingheavy modulating pulses tothe transmitter and for ieviating 'the cathodev 4ray from its origin on theiscreen i502 at the moment theradio -pulse is transmitted intospace Instead Vof separa-te antennas and directing means 3 and 5 -for l"the transmitter .and the receiver a common antenna and directing means can 'be used vboth `for transmission y,and reception as shown in Fig. 2. Y

By `means vof-avcam fnot shown) driven by 'the motor IS shifting-of the antenna and the directing means can be made in the shifting means I-Z-S in known manner at desired vintervals between the transmitter-and the receiver. Y i

AIf the transmitter and the `rece-iver are 'located on board a movable craft, Vthey can be combined with -a known compensating Ydevice for keeping the axis I6 in a vertical position, V for example'by a gyro or otherdevice.

The operation of the device `shown inFigs. :1 and 2 takes place `in ther'following manner.

A pulse modulated wave-transmittedfrom the transmitter I -is'received 'inthe rre'ceivei"byfthey detector 4 after reflection vfroniarrobject. The' transmitter and the receiver can be1given.a-ro tatingcor a back and forthmotionbymeans of the .axis I6.

the amplifier -I-I2 and, if'desired, -rectication in Vthe screen. Y

amplifier 49, a potential is delivered'to electrodes |66 so that the cathode ray is shown on the screen I2. When a pulse .is generated by the pulse emitting device' I24-I25, a heavy pulse is transmitted to the modulator 2 and a weak pulse to the deflecting plates IBS-IEM for simultaneously deflecting the cathode ray.

When an echo is received in the receiver 4, said echo is amplified, whereby it actuates the electrodes IGS of the cathode ray tube after such a time and after the cathode ray has been deflected to such 1a distance from 'is normal :position on the screen, which corresponds to the echo-time.

The cathode ray is moved towards the periphery of the screen and will be visible only when anechoarrives.

' If Vthe movement of the axis I isnmade sufriciently rapidly, a light spot will be visible on the :screen each .time Vthe radio wave passes the object, and if the fluorescent screen has been made with suiiicient .delaying a-ction, a fixed light spot The motor I 9 can either directly or by the aid of a saw-tooth generator vsynchronized :by "the motorinake `thercathode ray -move radially baci;

and forth between the center and the periphery of the screen of the cathode ray tube. When the motor :has a certain angle', the cathoderaywill thus be in the center. At this angle the :motor will connect the transmitter fora short-moment overa cam wheel. g

YIn'this case vthe same Vreiiector canbe used'for both transmission and reception as shown in xFig.

2. The cam Wheel `:of .the motor willthen switchray' between 'the center and the periphery of the screen, thecurrent from a synchronously operating pulse generator vcan then direct the transmittingpulses.

.Theconnection and disconnection of the transmitter can take place by means of a shifting device inthe forni of an electron tube relay inserted in the sending circuit, in order alternately "to disconnect athertransmitter Vand connect the receiVer-*to the respective circuits. Said'relays lcan consist ofV electron tubes or gas-filled tubes, which normally Ahave high'negativeV grid voltage Aand a' high interior resistance, but during the `switching Y period receives' from the saw-tooth' generator such agrid potential that Ythe inner resistance is suiciently lowered, and a pulse is emitted tothe transmitter. When using such electron-tube relays, switching rates ofY any desired magnitude canibeobtained in lpratice.

The axis 'I 6, y-whichcarries the'transmitter and the receiver can, ofcourse, be made vto rotate continuously or reciprocatingly so that only thel desired region can be observed.

The direction of the desir-edobject, forexample, with respectto-thejtrackV of a craft, can `according tothisinvention be obtained by meansof anl indicating'device'combined with the rotating axis,

- whichcarries the received or combined with an After amplicationof the'wave in axis driven V'synchronouslywith saidv axis. 1 f The fluorescent screen can be lprovided with a lscalefusing polar coordinates'whereby the 'radius motorl of the projection of the ray on the screen from the origin, indicates the distance to the object. By observing the angular position of the ray with respect to the polar coordinate scale, the angular position of an object with respect to the track of a craft can thus be observed.

`We claim:

1. A system for the determination of directions and distances to objects in space comprising, in combination, means for transmitting and receiving pulse modulated radio waves, highly directional antenna means for the transmission of said waves in a certain direction and for the reception of reflected waves from about the same direction as the transmitted waves, a support, a rotatable shaft on saidrsupport, said antenna means being mounted on said shaft, means to rotate said shaft at a predetermined rate, pulse generating means coupled to the transmitting and receiving means and comprising a saw-tooth generator and a pulse generator, circuit means interconnecting said generators with each other for maintaining their outputs in predetermined fixed phase relationship, means of indication comprising a ray indicating screen and a ray emitting source for the emission of rays projectable as visible light spots on said screen, deviation means including deflecting means for moving said ray radially, and control means coupled to the receiving means for the control of the intensity of the ray, and synchronizing means coupled to the movable parts of the antenna means and to said saw-tooth generator and to the said deviation means for rotating the ray synchronously with the directional antenna means and for deviating the ray in fixed angular relationship with respect to the direction of the antenna means, whereby a pulse is transmitted simultaneously as the ray leaves its normal position in the direction of a reflecting object, and a light spot is produced on the screen at a distance from its normal position proportional to the distance to said reflecting object upon the receipt of a reected wave.

2. The system as claimed in claim l, in which the transmitting and receiving means are provided with Common highly directional antenna means, shifting means connected to said transmitting and receiving means and to said antenna means and adapted at certain time intervals alternately to disconnect the transmitting means from and to connect the receiving means to the said common antenna means and vice Versa.

3. A system for the determination of directions and distances tc objects in space comprising, in combination, means for transmitting and receiving pulse modulated radio waves, highly directional antenna means for the transmission of said waves in a certain direction and for the reception of reflected waves from about the same direction as the transmitted waves, a support, a rotatable vertical shaft on said support, said antenna means being mounted on said shaft, means to rotate said shaft at a predetermined rate, pulse generating means coupled to said antenna means and comprising a saw-tooth generator and a pulse generator, and means whereby said generators are adapted to be synchronized with each other, means of indication comprising a ray indicating fluorescent screen with delaying action and a ray emitting source for the emission of rays projectable as visible light spots on said screen, deviation means adapted to deviate such a ray radially, and control means coupled to the receiving means for the control of the intensity of the ray, and synchronizing means coupled to.

the movable parts of the antenna means and to said saw-tooth generator and to the said deviation means for rotating the ray synchronously with the directional antenna means and for deviating the ray in the same instant direction as that of the antenna means, whereby a pulse is transmitted simultaneously as the ray leaves its normal position in the direction of a reflecting object, and a light spot is produced on the screen at a distance from its normal position proportional to the distance to said reflecting object upon the receipt of a reflected wave.

4. A direction and distance indicating device of the pulse modulation type, comprising: supporting means rotatable about a predetermined axis; means for rotating said supporting means; highly directional antenna means carried by said supporting means; transmitting means including pulse modulating means connected to said antenna means for causing the transmission of pulse modulated radio waves therefrom; receiving means connected to said antenna means for receiving transmitted waves reflected thereto; a cathode ray device comprising, a retentive fiuorescent screen, means for producing a cathode ray normally impinging on said screen at a predetermined point centrally located thereon, means for deflecting said ray along mutually perpendicular axes on said screen passing through said predetermined point, said deection being independently controllable with respect to each axis, and means for controlling the intensity of said ray; orienting means connected to said deflecting means and comprising rotary means revolving in xed angular relationship with respect to said supporting means for causing said ray to be deflected in a direction fixedly angularly related to the direction of said antenna means; a first generator for producing potentials of saw tooth wave shape connected to said deiiecting means and to said orienting means for cyclically increasing the magnitude of said deflection in a linear manner at a predetermined rate; a second generator connected to said pulse modulating means and producing pulses of potential controlling said transmitting means; a first circuit means interconnecting said first and second generators and causing said second generator to produce a pulse at each instant when the output of said first generator causes said deecting means to start movement of said ray radially outwardly from said predetermined point on said screen; and a second circuit means connecting said receiving means to said intensity control means for producing a luminous point on said screen upon receipt of a reflected wave, the angular position of said luminous point being determined by the direction of sai-d antenna means and the radial distance thereof from said predetermined point being proportional to the total distance travelled by the transmitted and reected Waves.

5. A device according to claim 4, wherein said cathode ray device further comprises a centrally apertured diaphragm disposed intermediate said screen and said deflecting means for blocking said ray in the absence of any wave received by said receiving means.

6. A device according to claim 4, wherein said orienting means comprises: two spaced circular resistors carried by said supporting means concentrically with the axis of rotation thereof; diametrically opposed points of connection on each resistor, the diameter interconnecting said zesmez Vcircuit means connecting said opposed points of connection on each ,resistor to said `rst generator.

.PER HARRY CLAESSON.

,References oma ,in the me of this patent UNITED STATES PATENTS Number 10 Number yName Date Lyman Y Feb.18, 1941 King 2 May 27, `194? Hoisington Aug. '26, 1947 Busignies Feb, '1"3, 1951 FOREIGN PATENTS Country y Date Australia Sept. 28, 1939 

